Heat exchange system and method of assembly

ABSTRACT

A method of constructing a coil wound heat exchange module and transporting and installing the coil wound heat exchange module at a plant site, such as an natural gas liquefaction plant. A module frame is constructed and attached to a heat exchanger shell prior to telescoping of a coil wound mandrel into the shell. The module frame includes a lug and two saddles that remain attached to the shell throughout the process and when the heat exchanger is operated. The lug and saddles are constructed and located to stabilize the shell during construction, telescoping and transport (when in a horizontal orientation), and when the shell is installed at the plant site (in a vertical orientation). The lugs and saddles are adapted to allow for thermal expansion and contraction of the shell when it is transitioned from ambient to operating temperature and vice versa.

FIELD OF THE INVENTION

The present disclosure relates generally to heat exchangers andcryogenic equipment, and, more particularly, to assembling heatexchangers and cryogenic equipment.

BACKGROUND

Conventional methods of assembling and installing a coil wound heatexchanger (“CWHE”) are time consuming and lead to increasedmanufacturing duration. Under a typical method, the shell supported byset of shop saddles while a wound bundle is telescoped into the pressurecontaining shell (“shell”). After the wound bundle is telescoped intothe shell, the CWHE is lifted onto a transport vehicle, where it isstrapped to a set of transport saddles and transported in a horizontalposition. When the CWHE arrives at a plant site, it is erected into avertical position and a support frame is built around it. The supportframe includes structural elements that are designed to provide verticalsupport for the CWHE, as well as to account for wind and seismic loads.

Conventional CWHE assembly methods require that piping connections,electrical connections, instrumentation, walking platforms, etc. beinstalled after the CWHE has been erected at the plant site and at leastsome of the support frame has been built. This results in relativelylong construction timelines and means that the installation of theseitems must take place outdoors at the plant site. In addition, threedifferent sets of structures are used to support the CWHE during thevarious stages of construction and lifting equipment must be directlyattached to the shell when the shell is lifted onto the transportvehicle and when it is erected at the plant site.

There is a need for an improved method of assembling and installing aCHWE.

SUMMARY

Improved methods are provided herein for assembling a heat exchanger andcryogenic equipment, as well as an improved module frame and structurefor connecting the heat exchanger to the module frame.

In one aspect, the improvement comprises the following method step:

-   -   (a) forming a first mandrel;    -   (b) forming a first wound bundle onto the first mandrel to form        a first coil wound mandrel by winding tubing around the first        mandrel;    -   (c) providing a first portion of a first heat exchanger shell,        the first portion having a first open face and a first shell        longitudinal axis that extends parallel to a largest dimension        of the first heat exchanger shell;    -   (d) attaching the first portion of the heat exchanger shell to a        first module frame with at least two connecting members that are        rigidly attached to the first heat exchanger shell to form a        first heat exchange module, the first module frame comprising a        plurality of columns connected by cross-members;    -   (e) after performing step (d), telescoping the first coil wound        mandrel into the first portion of the first heat exchanger shell        through the first open face while the first shell longitudinal        axis is in a substantially horizontal orientation;    -   (f) after performing step (e), closing the first open face of        the first heat exchanger shell;    -   (g) after performing step (f), transporting the first heat        exchange module to a plant site; and    -   (h) after performing step (g), mounting the first heat exchange        module at the plant site with the first shell longitudinal axis        in a substantially vertical orientation, wherein the first heat        exchanger is suspended in a fixed position within the first        module frame by the at least two connecting members.

In another aspect, the improvement comprises a heat exchange modulecomprising a coil wound heat exchanger having a shell having an outersurface, a top end, bottom end, a shell longitudinal axis, and a shelllength extending along the longitudinal axis from the top end to thebottom end (the shell length being a largest dimension of the shell).The heat exchange module further comprises a module frame having aplurality of columns connected by cross-members, a lug that is rigidlyattached to the shell and the module frame; and, a first saddle that isrigidly attached to the shell and is connected to the module frame by aplurality of first saddle joints. Each of the plurality of first saddlejoints is adapted to accommodate for thermal expansion and contractionof the shell by enabling the first saddle to move relative to the moduleframe in a direction that is parallel to the longitudinal axis of theshell.

In yet another aspect, the improvement comprises a plant for liquefyinga hydrocarbon feed gas in which the main heat exchanger is constructed,transported to the plant side, and installed using the methods disclosedherein and the module frame structure disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are described herein making reference to the appendeddrawings.

FIGS. 1A-1E illustrates a method of assembling a single shell heatexchanger assembly according to one or more embodiments;

FIGS. 2A-2C illustrates a method of assembling a multiple shell heatexchanger assembly according to one or more embodiments;

FIGS. 3A-3D illustrates a method of assembling a multiple shell heatexchanger assembly according to one or more embodiments;

FIG. 4A is an isometric view of a CWHE installed at a plant site;

FIG. 4B is a sectional view taken along line B-B of FIG. 4A;

FIG. 4C is a sectional view taken along line C-C of FIG. 4B;

FIG. 4D is a partial isometric view of area C-C of FIG. 4B;

FIG. 4E is an enlarged partial view of area E-E of FIG. 4D;

FIG. 4F is a partial isometric view of area E-E of FIG. 4D;

FIG. 4G is a sectional view taken along line G-G of FIG. 4B;

FIG. 4H is a partial isometric view of area G-G of FIG. 4B;

FIG. 5 is a block diagram of an exemplary natural gas liquefactionsystem, with which the heat exchanger assembly that could be usedaccording to one or more embodiments; and

FIG. 6 is a flow chart showing the steps of an exemplary methodsdescribed herein.

DETAILED DESCRIPTION

In the following, details are set forth to provide a more thoroughexplanation of the exemplary embodiments. However, it will be apparentto those skilled in the art that embodiments may be practiced withoutthese specific details. In other instances, well-known structures anddevices are shown in block diagram form or in a schematic view ratherthan in detail in order to avoid obscuring the embodiments. In addition,features of the different embodiments described hereinafter may becombined with each other, unless specifically noted otherwise.

Further, equivalent or like elements or elements with equivalent or likefunctionality are denoted in the following description with equivalentor like reference numerals. As the same or functionally equivalentelements are given the same reference numbers in the figures, a repeateddescription for elements provided with the same reference numbers may beomitted. Hence, descriptions provided for elements having the same orlike reference numbers are mutually exchangeable.

The following detailed description is not to be taken in a limitingsense. In this regard, directional terminology, such as “top”, “bottom”,“lower,” “upper,” “below”, “above”, “front”, “behind”, “back”,“leading”, “trailing”, “horizontal,” “vertical,” etc., may be used withreference to the orientation of the figures being described. Termsincluding “inwardly” versus “outwardly,” “longitudinal” versus “lateral”and the like are to be interpreted relative to one another or relativeto an axis of elongation, or an axis or center of rotation, asappropriate. Because parts of embodiments may be positioned in a numberof different orientations, the directional terminology is used forpurposes of illustration and is in no way limiting. It is to beunderstood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope defined bythe claims.

Terms concerning attachments, coupling and the like, such as “connected”and “interconnected,” refer to a relationship wherein structures aresecured or attached to one another either directly or indirectly throughintervening structures, as well as both moveable or rigid attachments orrelationships, unless expressly described otherwise, and includes termssuch as “directly” coupled, secured, etc. The term “operatively coupled”is such an attachment, coupling, or connection that allows the pertinentstructures to operate as intended by virtue of that relationship.

The term “substantially” may be used herein to account for manufacturingtolerances (e.g., within 5%) that are deemed acceptable in the industrywithout departing from the aspects of the embodiments described herein.In the context of an orientation, the term “substantially” means within5 degrees of that orientation. For example, “substantially vertical”means within 5 degrees in either direction of vertical.

As used herein, the term “orientation”, in reference to an orientationof a structure, is intended to mean that the orientation of thestructure is defined by the structure's longest dimension.

The term “fluid flow communication,” as used in the specification andclaims, refers to the nature of connectivity between two or morecomponents that enables liquids, vapors, and/or two-phase mixtures to betransported between the components in a controlled fashion (i.e.,without leakage) either directly or indirectly. Coupling two or morecomponents such that they are in fluid flow communication with eachother can involve any suitable method known in the art, such as with theuse of welds, flanged conduits, gaskets, and bolts. Two or morecomponents may also be coupled together via other components of thesystem that may separate them, for example, valves, gates, or otherdevices that may selectively restrict or direct fluid flow.

The term “conduit,” as used in the specification and claims, refers toone or more structures through which fluids can be transported betweentwo or more components of a system. For example, conduits can includepipes, ducts, passageways, and combinations thereof that transportliquids, vapors, and/or gases.

The term “natural gas”, as used in the specification and claims, means ahydrocarbon gas mixture consisting primarily of methane.

The term “mixed refrigerant” (abbreviated as “MR”), as used in thespecification and claims, means a fluid comprising at least twohydrocarbons and for which hydrocarbons comprise at least 80% of theoverall composition of the refrigerant.

The terms “bundle” and “tube bundle” are used interchangeably withinthis application and are intended to be synonymous.

The term “compression circuit” is used herein to refer to the componentsand conduits in fluid communication with one another and arranged inseries (hereinafter “series fluid flow communication”), beginningupstream from the first compressor or compression stage and endingdownstream from the last compressor or compressor stage. The term“compression sequence” is intended to refer to the steps performed bythe components and conduits that comprise the associated compressioncircuit.

As used herein, the term “vertical orientation” is intended to mean thata structure's longest dimension is oriented vertically.

As used herein, the term “horizontal orientation” is intended to meanthat a structure's longest dimension is oriented horizontally.

As used herein, the term “rigidly attached” is intended to mean that astructure is mechanically coupled to the other structure in a way thatprevents any motion between the two structures, such as bolting orwelding. Unless otherwise specified, a first element is considered to be“rigidly attached” to a second element even if the attachment isindirect (i.e., additional elements are located between the first andsecond elements).

As used herein, the term “ambient temperature” refers to the airtemperature of the environment surrounding the equipment.

FIGS. 1A-1E and FIG. 6 illustrate an exemplary method of assembling asingle shell heat exchange module 100 (FIG. 1D). In this embodiment, theheat exchange module 100 comprises a coil wound heat exchanger (CWHE).CWHEs are often employed for natural gas liquefaction. CWHEs typicallycontain helically wound tube bundles housed within an aluminum orstainless steel shell that forms a pressure vessel. For liquid naturalgas (LNG) service, a CWHE may include multiple tube bundles, each havingseveral tube circuits. Cooling might be provided using any one of avariety of refrigerants, for example, a mixed refrigerant (MR) streamhaving a mixture of nitrogen, methane, ethane/ethylene, propane, butanesand pentanes is a commonly used refrigerant for many base-load LNGplants. The refrigeration cycle employed for natural gas liquefactionmight be a cascade cycle, single mixed refrigerant cycle (SMR),propane-precooled mixed refrigerant cycle (C3MR), dual mixed refrigerantcycle (DMR), nitrogen or methane expander cycles, or any otherappropriate refrigeration process. The composition of the MR stream isoptimized for the feed gas composition and operating conditions. Locatedat the top of each tube bundle within the shell is a distributorassembly that distributes the refrigerant over the tube bundle in thespace between the shell and the mandrel, which provides refrigerationfor the fluids flowing through the tube bundles. An example of adistributor assembly is disclosed in US Publication No. 2016/0209118,which is incorporated by reference as if fully set forth.

FIGS. 1A-D illustrate a first exemplary method of assembling a heatexchange module 100 comprising a CWHE having two coil wound mandrels114, 124. In order to form each coil wound mandrel, 114, 124, tubing 112is spirally wound about a mandrel 110. In most applications, multiplecircuits of tubing will be wound about the mandrel 110. Each coil woundmandrel 114 has inlets located at or proximate to a first end 110 a ofthe mandrel 110 and outlets located at or proximate to a second end 110b of the mandrel 110.

As shown in FIG. 1B, two saddles 136 a, 136 b are affixed to a first(lower) portion 131 of the pressure vessel shell (“shell”), then thefirst coil wound mandrels 114 is telescoped (i.e., inserted) into thefirst portion 131 of the shell through an open top end of the firstportion 131 along a longitudinal axis L of the lower portion 131.Similarly, as shown in FIG. 1C, two saddles 136 c and 136 d affixed to asecond (upper) portion 134 of the shell, then the second coil woundmandrel 124 is telescoped into the second portion 134. After both coilwound mandrels 114, 124 have been inserted into the first and secondportions 131, 134 of the shell, respectively, the first and secondportions 131, 134 are joined to form the pressure vessel shell 132 (SeeFIG. 1D). After the shell 132 is fully formed and closed, it istransported to a plant site in a horizontal orientation (the orientationshown in FIG. 1D). Upon arrival at the plant site and as shown in FIG.1E, the heat exchange module 100 is erected into a vertical orientationand installation is completed.

In this exemplary embodiment, the module frame structure that supportsthe heat exchange module 100 at the plant site is not shown. The moduleframe could be assembled and affixed to the first and second portions131, 134 of the shell 130 prior to telescoping of the coil woundmandrels 114, 124, or the module frame could be assembled and affixed toshell 130 after it is erected at the plant site.

A key improvement of the assembly method described in connection withthe heat exchange module 100 shown in FIGS. 1A-E is that the saddles 136a-136 d are attached each portion 131, 134 of the shell 132 prior totelescoping the coil wound mandrel 114, 124 into each portion, thatthose saddles 136 a-136 d are never removed from the shell 132, and thatthe saddles 136 a-136 d are attached to the module frame when it isinstalled. In other words, the saddles 136 a-d that are used to supportthe portions 131, 134 of the shell 132 during telescoping remain part ofthe structural support of the CWHE throughout the construction andinstallation process, as well as when the CWHE is operated. Accordingly,the saddles 136 a-136 d are adapted to provide support for the CWHEduring transport (when it is in a horizontal orientation) and after theCWHE has been erected and installed at the plant site (in which the CWHEis in a vertical orientation). This is in contrast to conventionassembly methods, in which three different set of saddles are used inthe telescoping, transportation, and final installation stages.

As shown in FIGS. 1B & 1C, the saddles 136 a are configured to supportboth horizontal and vertical loads of the CWHE shell 130. To this end,each of saddles 136 a-136 b includes a frame portion (see frame portions137 a, 137 b) that is framed around (i.e., fully encircles) the shell132 and a base portion (see base portions 138 a, 138 b) that makescontact with a load bearing surface (e.g., a platform, ground, and/or amodule frame) and supports horizontal and vertical loads when the shell132 is in a horizontal orientation.

Using a single set of saddles throughout the assembly, transportation,and site installation stages provides several advantages. For example,insulation can be installed on shell 132 prior to transportation of theCWHE to the plant site because it won't be disturbed by removal andinstallation of different saddles and additional connection to themodule frame.

FIGS. 2A-2C illustrate the exemplary assembly method on a heat exchangemodule 200 having a different configuration. This exemplary embodimentis very similar to the method described in FIGS. 1A-1E, the primarydifference being that, in this exemplary embodiment, the CWHE has twoseparate shells (pressure vessels) 230, 240, each containing one coilwound mandrel 214. In this embodiment, the coil wound mandrels areformed as shown in FIG. 1A. As shown in FIG. 2A, two saddles 236 a, 236b are affixed to the first shell 230, then the first coil wound mandrel210,214 is telescoped into the first shell 230 through an open topend/face. When telescoping is complete, the top end of the shell 230 issealed by, as shown in FIG. 2B. The process is repeated for the secondshell 240. The assembled shells 230, 240 are transported to the plantsite in the same manner as the shell 130 and as shown in FIG. 1D. Uponarrival at the plant site and as shown in FIG. 2C, each of the shells230, 240 are erected into a vertical orientation. Two saddles 236 c, 236d are affixed to the second shell 240.

In this exemplary method, the module frame structure that supports theCWHE shells 230, 240 at the plant site is not shown. The module framecould be assembled and affixed to the shells 230, 240 prior totelescoping of the coil wound mandrels or the module frame could beassembled and affixed to shells 230, 240 after the heat exchange module200 is erected at the plant site. Referring to FIG. 2C, because the CWHEcomprises two shells 230, 240, the second shell 240 is positioned atopthe first shell 230. Accordingly, if the module frame for each shell230, 240 is installed prior to transport of the shells 230, 240 to theplant site, the module frame of the second shell 240 is preferablyattached to the top of the module frame for the first shell 230. Oncethe shells 230, 240 are installed at the plant site, external piping 254a-b that interconnects the shells 230, 240 is installed.

FIGS. 3A-3D illustrate another exemplary method of assembling a heatexchange module 300 having a multiple shell CWHE. In this embodiment,the steps of the assembly process are nearly identical to those of theembodiment shown in FIGS. 2A-2C, except the module frames 360 a-b areconstructed and connected to the saddles 338 a-b prior to telescopingthe coil wound mandrels 310, 320 into the respective shells 330, 340(see FIGS. 3A-C). Constructing the module frame 360 a and connecting thesaddles 338 a-b to the module frame 360 a prior to telescoping enablesexternal piping 354 a-c, piping supports, valves, steps, ladders,standing platforms, and insulation to be installed prior totransportation of the shells 330, 340 to the plant site because themodule frame 360 a protects the shell 330 and provides attachment pointsfor the elements being installed. In this embodiment, the module frame360 a, the fully formed shell 330, and the saddles 336 a-b form a heatexchange module 366 a. A second heat exchange module 366 b is formedusing the same steps as the heat exchange module 366 a.

Installation at the plant site is further simplified with this method.The first heat exchange module 366 a is erected into a vertical positionand the first module frame is affixed to a platform 361 at the plantsite (typically a concrete pad or footer). Then the second heat exchangemodule 366 b is erected into a vertical position and the second moduleframe 366 b is mounted to top of the first module frame 366 a. Once theshells 230, 240 are installed at the plant site, external piping 354 d-eand electrical connections (not shown) that interconnect the shells 330,340 are installed.

FIG. 3C illustrates another exemplary method for forming a heat exchangemodule 300. The purpose of this embodiment in which the multiple shellheat exchange module 300 includes two pressure vessels (shells) 330,340, a first module frame 360 a and a second module frame 360 b aremanufactured. Each module frame 360 includes a plurality of beams 362and trusses 364 to increase the overall strength of the structure. Theplurality of beams 362 that define a frame volume of the module frame360. Trusses 364, if included, may also define the frame volume sincethey do not extend beyond the frame volume defined by the beams 362.Thus, the framing of each module frame 360 forms a rectangular framewith a cavity (i.e., frame volume) configured to receive a correspondingpressure vessel. In other words, each module frame 360 is serves as anexoskeleton for its pressure vessel. Multiple module frames and supportmodules may be manufactured in parallel for each pressure vessel.

As will be described below, the first and second module frames 360 a,360 b are configured to be rigidly connected to a corresponding one ofthe first and second shells 330, 340, thereby forming a first heatexchange module. In this embodiment, the plurality of beams 362 aresized and arranged such that no part of the pressure vessel shellextends outwardly beyond the frame volume. In some embodiments, apressure vessel, including external piping and wiring is confined withinthe frame volume, while in other embodiments, some eternal piping andwiring may extend beyond the frame volume. Thus, the module frame 360itself is a frame enclosure configured to enclose a pressure vesseltherein, such that the module frame 360 defines an outermost boundary ineach dimension of the corresponding pressure vessel shell. In otherwords, at the very least, the corresponding pressure vessel shell doesnot extend beyond the module frame 360 in any dimension. In alternativeembodiments, it may be desirable to have the shell protrude from the topof the module frame in order to facilitate connections to other elementsof the plant.

In addition, each of the first and second shells 330, 340 is suspendedwithin the frame volume of its corresponding module frame, such that thepressure vessel is supported by the module frame both when in ahorizontal orientation and in a vertical orientation. In addition, eachsaddle 136 is rigidly attached to its corresponding module frame 360(see e.g., FIG. 3D). Also, when the wound bundle 314 is being telescopedinto the shell 330, it may be desirable to pull the wound bundle 314through the shell 330 using cables that extend through a opening at thebottom end of the shell 330.

Another exemplary embodiment is shown in FIGS. 4A-4H. In thisembodiment, exemplary structures used to execute the assembly methodsdisclosed in FIGS. 1A-3D are disclosed in greater detail. FIGS. 4A-Bshow a fully assembled CWHE, which consists of two heat exchange modules466 a, 466 b. Each heat exchange module 466 a, 466 b comprises a shell430, 440, a module frame 460 a, 460 b, two saddles 436 a-d, and a lug441 a, 441 b. As will be described herein, the saddles 436 a-d, and thelug 441 a, 441 b connect the shells 430, 440 to their respective moduleframes 466 a, 466 b and are adapted to accommodate for multiple types ofloads throughout the assembly process and during operation. Thestructure of the second heat exchange module 466 b will be described indetail herein. The described structure is nearly identical in nature inthe first heat exchange module 466 a, understanding that some dimensionsmay be different due primarily to the fact that the shells 430, 440 havedifferent dimensions.

One of the saddles 436 d is shown in FIGS. 4C-E. It should be understoodthat the other saddle 436 c of the upper heat exchange module 466 b andthe saddles 436 a-b of the lower heat exchange module 466 a have thesame structural elements and only differ in dimension/proportions andlocation. For example, the saddles 436 a-b will have larger dimensionsdue to the larger circumference of the shell 430. The saddle 436 dincludes a frame portion 437 which encircles the shell 440. The saddle436 d further includes sliding joint plates 438 a-b which engage slidingjoints 467 a-d and connect the saddle 436 d with a cross member 462 ofthe module frame 466 d. Optionally, a base plate 438 can be provided atthe connection to the cross member 462 to provide additional structuralstrength.

The saddle 436 d further includes a contoured plate 472, which isarcuate and complimentary in shape to the outer surface of the shell 440along an interface. The interface preferably overlaps at least onequarter and, more preferably, at least one third of the circumference ofthe shell 440. The saddle 436 d further includes a plurality of ribs439, which extend linearly from the base plate 438, are welded to thesliding joint plates 443 a-b, then continue to the contour plate 472 ina direction that is perpendicular to the base plate 438. The saddle 436d is rigidly affixed to the shell 340, either with welds and orfasteners.

Each of the sliding joints 467 a-d includes a plurality of bolts 468 (inthis embodiment, two bolts per sliding joint), which extend throughslots 469 formed in the sliding joint plates 445 a-b. Each slot 469 hasa length that is significantly greater than the diameter of the bolt 468that engages that slot 469. The length of the slot 469 is preferably atleast 1.5 times (more preferably at least twice) the diameter of thebolt 468. Alternatively, an elongated slot 469 could be formed in one ofthe sliding joint plates 445 a-b and holes that are much closer to thediameter of the bolts 468 could be provided. The joint plates 445 a-b,slots 469, and bolts 468 combine to define a shear block. Theconfiguration of the sliding joints 436 a-d enables the saddle 436 d tomove relative to the module frame 466 b in a direction parallel to thelength of the shell 430, but prevents any other substantial movement ofthe saddle 436 d relative to the module frame 466 b. The movementallowed by the slots 469 is preferably sufficient to accommodate thermalcontraction and expansion of the shell 440 that is expected to occurwhen the shell 440 is transition to operating temperature.

FIGS. 4G-H show the structure of the lug 441 b in detail. The lug 441 bcomprises cross-members 442 a-d and beams 443 a-d that “box” in theshell 440. The beams 443 a-d are each welded to two cross-members 442a-d and are either welded or bolded to the shell 440. The cross-members442 a-d are also preferably welded or bolted to the module frame. Thisstructure rigidly attaches the lug 441 b to both the shell 440 and themodule frame 460 b.

The lug 441 b and the two saddles 436 c-d attach the shell 440 to themodule frame 460 b and cooperate to accommodate multiple different typesof loads during assembly, transportation, and operation of the heatexchange module 400. When the shell 440 is being assembled andtransported (see shell 330, FIGS. 3B-C), the saddles 436 c-d provide theprimary support and stability for the shell 440. When the shell 440 isinstalled in a vertical orientation at the plant site (see FIG. 4A), thelug 441 b provides the primary vertical support. The saddles 436 c-dcooperate with the lug 441 b to provide support against wind and seismicloads. The sliding joints 467 a-d and the position of each saddle 436c-d allows for thermal expansion of the shell 440.

The preferred location of the lug 441 b and the saddles 436 c-d willdepend upon a number of factors, including the geometry of the shell440, its position in the module frame 460 b, and the location of pipingprotrusions on the surface of the shell 440. In general, it ispreferable that the lug 441 b be located within 5% (more preferablywithin 2%) of the center of mass of the shell 440. The lower saddle 436c is located between the lug 441 b and the bottom end of the shell 440and is preferably within 5% (more preferably within 2%) of the midpointbetween the location of the lug 441 b and the bottom end of the shell440. The upper saddle 436 c is located between the lug 441 b and the topend of the shell 440 and is preferably within 5% (more preferably within2%) of the midpoint between the location of the lug 441 b and the topend of the shell 440. By way of example, if the shell 440 has a lengthof 10 meters and a center of mass at its midpoint, the lug 441 b wouldbe preferably located within 0.5 meters, and more preferably within 0.2meters, of the midpoint.

As noted in previous embodiments, each shell 430, 440 is containedwithin a perimeter defined by the cross members 462 a-d (see FIG. 4D) ofthe module frame 466 a-b. This provides protection for the shells430,440 during construction and transport. It should be understood thata shell 430, 440 may extend beyond an end of the frame module 466 a-b,such at the top of shell 430, which extends beyond the upper end of itsframe module 466 b. This most common for a shell of a single-shell heatexchanger or the uppermost shell of a multiple-shell heat exchanger.

The methods described herein allow for all internal piping and almostall external piping to the shells to be completed prior to thecompletion of the coil wound exchanger bundle. In addition, valves andinstruments can be installed and insulated before the long lead bundlesare telescoped into the shells. Additionally, this method can eliminatethe need for temporary shipping saddles. In addition, the use ofmultiple pressure vessels including any combination thereof within themodule frames can be accommodated. Furthermore, once at the operationsite the final piping connections are made and the exchanger modules canbe made operational.

As noted above, the heat exchange modules 100, 200, 300, 400 disclosedherein are most commonly used as part of a natural gas liquefactionplant (system). An exemplary natural gas liquefaction system 2 is shownin FIG. 5. Referring to FIG. 5, a feed stream 1, which is preferablynatural gas, is cleaned and dried by known methods in a pre-treatmentsection 7 to remove water, acid gases such as CO2 and H2S, and othercontaminants such as mercury, resulting in a pre-treated feed stream 3.The pre-treated feed stream 3, which is essentially water free, ispre-cooled in a pre-cooling system 18 to produce a pre-cooled naturalgas stream 5 and further cooled, liquefied, and/or sub-cooled in a CWHE8 (which could be heat exchange module 100 or 200) to produce an LNGstream 6. The LNG stream 6 is typically let down in pressure by passingit through a valve or a turbine (not shown) and is then sent to LNGstorage tank 9. Any flash vapor produced during the pressure letdownand/or boil-off in the tank is represented by stream 45, which may beused as fuel in the plant, recycled to feed, or vented.

The pre-treated feed stream 1 is pre-cooled to a temperature below 10degrees Celsius, preferably below about 0 degrees Celsius, and morepreferably about −30 degrees Celsius. The pre-cooled natural gas stream5 is liquefied to a temperature between about −150 degrees Celsius andabout −70 degrees Celsius, preferably between about −145 degrees Celsiusand about −100 degrees Celsius, and subsequently sub-cooled to atemperature between about −170 degrees Celsius and about −120 degreesCelsius, preferably between about −170 degrees Celsius and about −140degrees Celsius. CWHE 8 is a coil wound heat exchanger with threebundles. However, any number of bundles and any exchanger type may beutilized.

Refrigeration duty for the CWHE 8 is provided by a mixed refrigerantthat is cooled and compressed in a compression system 31. The warm mixedrefrigerant is withdrawn from the bottom of the CWHE 8 at stream 30,cooled and compressed, then reintroduced into the tube bundles throughstreams 41, 43. The mixed refrigerant is withdrawn, expanded, andreintroduced in the shell side of the CWHE 8 via streams 42, 44.Additional details concerning the natural gas liquefaction system can befound in US Publication No. 2018/0283774, which is incorporated hereinby reference as if fully set forth. The system 2 shown in FIG. 5 isidentical to the system shown in FIG. 1 of US Publication No.2018/0283774.

In view of the of the disclosed embodiments, the integration of thepressure containing shell (i.e., pressure vessel) into the module frameinclusive of piping outside as well as internal to the CWHE reducesmanufacturing time, cost, and field work through simultaneous mechanicalwork and winding of the bundle. Once the wound bundle is completed itcan be telescoped into the pressure shell that is already disposedwithin the module frame for final assembly. This method allows forcompletion of electrical and mechanical work, including both electricalsystems and piping systems (both internal and external) within themodule frame prior to completion of manufacturing of the mandrel withthe wound bundle. It also allows for the manufacturing of the pressureshell and assembly to be completed at different sites to optimize laboravailability and cost. In addition, the use of saddles that areconfigured to support both horizontal and vertical loads of the pressurevessels aids in: performing the electrical and mechanical work on thepressure shell within the module frame, supporting the horizontalpressure vessel during shipping of the pressure vessel within the moduleframe, and supporting the erected pressure vessel within the moduleframe at the operation site, including during operation.

FIG. 6 provides a flow diagram of an exemplary method of assembly,transport, and installation of a heat exchange module in accordance withthe exemplary embodiments described herein. The process commences withconstruction of the shell (step 1012) and winding of tubes around themandrel to form a wound bundle (step 1014). When the shell has beenformed, the module frame, including the saddles and lug, is constructed(step 1016) and attached to the shell (step 1018). When the wound bundleis finished, it is telescoped (inserted) into the shell (step 1022) andthe top end of the shell is closed (step 1024).

Constructing and attaching the module frame to the shell prior totelescoping the wound bundle into the shell provides a number ofbenefits. The structural stability of the module frame reduces stress onthe shell during telescoping, transition to transportation, duringtransportation, and during erection of the shell at the plant side. Insome applications, this will enable the shell to be thinner (andtherefore lighter) and less costly. For example, the bracing force usedto stabilize the shell during the telescoping step 1022 can be appliedto the module frame instead of being applied directly to the shell.Similarly, when the shell is being moved (lifted) in preparation fortransportation (step 1028) and erected and installed at the plant site(step 1032), the moving/lifting forces can be applied to the moduleframe instead of being applied directly to the shell. In addition, ininstallations where the heat exchanger consists of multiple shells (seeFIGS. 2A-C and 4A-H), the upper shell (e.g., shell 440 of FIG. 4A) canbe installed by simply bolting its module frame to the module frame ofthe lower shell (e.g., shell 430 of FIG. 4A).

Constructing and attaching the module frame to the shell prior totelescoping also enables some process steps that are required to beperformed in series using conventional methods to be performed inparallel. For example, piping penetrations, piping supports, electricalconnections, instrumentation, and insulation can be installed on theshell (step 1020) prior to or in parallel with the telescoping step1022. Under conventional methods, these elements could not be installeduntil after the shell is installed at the plant site. This improvement,not only shortens the overall process length, it also enables additionalprocess steps to be performed in an indoor environment instead of beingperformed outdoors at a plant site. In addition, it enables the optionto pressure test the shell (step 1026) under shop conditions and beforetransport to the plant site (step 1030). Enabling a significant portionof the piping and electrical work can be done prior to transportationreduces the steps that need to be performed at the plant site. In manycases, the only piping and electrical connections that must be performedat the plant site are those that interconnect the shell with anothershell or with other elements of the plant (step 1034).

Furthermore, the following claims are hereby incorporated into thedetailed description, where each claim may stand on its own as aseparate example embodiment. While each claim may stand on its own as aseparate example embodiment, it is to be noted that—although a dependentclaim may refer in the claims to a specific combination with one or moreother claims—other example embodiments may also include a combination ofthe dependent claim with the subject matter of each other dependent orindependent claim. Such combinations are proposed herein unless it isstated that a specific combination is not intended. Furthermore, it isintended to include also features of a claim to any other independentclaim even if this claim is not directly made dependent to theindependent claim.

Although various exemplary embodiments have been disclosed, it will beapparent to those skilled in the art that various changes andmodifications can be made which will achieve some of the advantages ofthe concepts disclosed herein without departing from the spirit andscope of the invention. It will be obvious to those reasonably skilledin the art that other components performing the same functions may besuitably substituted. Thus, with regard to the various functionsperformed by the components or structures described above (assemblies,devices, circuits, systems, etc.), the terms (including a reference to a“means”) used to describe such components are intended to correspond,unless otherwise indicated, to any component or structure that performsthe specified function of the described component (i.e., that isfunctionally equivalent), even if not structurally equivalent to thedisclosed structure that performs the function in the exemplaryimplementations of the invention illustrated herein. It is to beunderstood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope of thepresent invention. It should be mentioned that features explained withreference to a specific figure may be combined with features of otherfigures, even in those not explicitly mentioned. Such modifications tothe general inventive concept are intended to be covered by the appendedclaims and their legal equivalents.

The invention claimed is:
 1. A method comprising: (a) forming a firstmandrel; (b) forming a first wound bundle onto the first mandrel to forma first coil wound mandrel by winding tubing around the first mandrel;(c) providing a first portion of a first heat exchanger shell, the firstportion having a first open face and a first shell longitudinal axisthat extends parallel to a largest dimension of the first heat exchangershell; (d) attaching the first portion of the first heat exchanger shellto a first module frame with at least two connecting members that arerigidly attached to the first heat exchanger shell to form a first heatexchange module, the first module frame comprising a plurality ofcolumns connected by cross-members; (e) after performing step (d),telescoping the first coil wound mandrel into the first portion of thefirst heat exchanger shell through the first open face while the firstshell longitudinal axis is in a substantially horizontal orientation;(f) after performing step (e), closing the first open face of the firstheat exchanger shell; (g) after performing step (f), transporting thefirst heat exchange module to a plant site; and (h) after performingstep (g), mounting the first heat exchange module at the plant site withthe first shell longitudinal axis in a substantially verticalorientation, wherein the first heat exchange module is suspended in afixed position within the first module frame by the at least twoconnecting members.
 2. The method of claim 1, wherein the at least twoconnecting members comprises at least one saddle and step (d) furthercomprises connecting the at least one saddle to the first module framewith a plurality of joints that enable the at least one saddle to moverelative to the first module frame in a direction that is parallel tothe first shell longitudinal axis while preventing movement of the atleast one saddle relative to the first module frame in directions thatare not parallel to the first shell longitudinal axis.
 3. The method ofclaim 1, wherein the at least two connecting members comprises at leasttwo saddles and step (d) further comprises connecting the at least twosaddles to the first module frame with a plurality of joints that enableeach of the at least two saddles to move relative to the first moduleframe in a direction that is parallel to the first shell longitudinalaxis while preventing movement of each of the at least two saddlesrelative to the first module frame in directions that are not parallelto the first shell longitudinal axis.
 4. The method of claim 1, whereinthe at least two connecting members comprise at least one lug and step(d) further comprises rigidly affixing the at least one lug to the firstmodule frame.
 5. The method of claim 1, further comprising: (i) beforeperforming step (g), installing on the first heat exchange module atleast one selected from the group of: piping, piping supports, valves,instrumentation, electrical systems, steps, ladders, standing platforms,and insulation.
 6. The method of claim 1, further comprising: (j) beforeperforming step (g), installing on the first heat exchange module atleast one selected from the group of: piping, piping supports, valves,steps, ladders, standing platforms, and insulation.
 7. The method ofclaim 1, further comprising, performing step (i) before finishing step(e).
 8. The method of claim 1, further comprising: (k) before performingstep (g), insulating an outer surface of the first heat exchange module.9. The method of claim 1, wherein step (h) comprises rigidly attachingthe first module frame to a platform at the plant site.
 10. The methodof claim 1, wherein step (d) further comprises configuring the firstmodule frame to contain the attached first portion of the first heatexchanger shell within a frame perimeter defined by the plurality ofcolumns of the first heat exchange module.
 11. The method of claim 1,further comprising: (l) providing a cable opening in the first heatexchanger shell at an end that is distal to the first open face andpassing a cable through the cable opening; wherein step (e) furthercomprises drawing the first coil wound mandrel into the first heatexchanger shell using the cable during at least a portion of step (m).12. The method of claim 1, further comprising: (m) repeating steps (a)through (f) to form a second heat exchange module; (n) after performingstep (m), transporting the second heat exchange module to a plant site;and (o) after performing step (n), mounting the second heat exchangemodule atop the first heat exchange module at the plant site with asecond shell longitudinal axis of the second heat exchange module in asubstantially vertical orientation, wherein the second heat exchangemodule is suspended in a fixed position within a second module frame ofthe second heat exchange module by the at least two connecting members.13. The method of claim 12, further comprising: (p) installing at leastone conduit that provide a fluid flow connection between the shell ofthe first heat exchange module and the shell of the second heat exchangemodule.
 14. The method of claim 1, further comprising: (q) during theperformance of step (e), bracing the first heat exchanger shell againsta force applied to the first heat exchanger shell by the telescoping thefirst coil wound mandrel solely by applying a bracing force to the firstmodule frame.
 15. The method of claim 1, further comprising: (r)pressure testing the first heat exchanger shell prior to performing step(g).
 16. The method of claim 1, further comprising: (s) forming a secondmandrel; (t) forming second coil wound mandrel by winding tubing aroundthe second mandrel; (u) providing a second portion of the first heatexchanger shell, the second portion having a second open face and asecond shell longitudinal axis that extends parallel to the largestdimension of the second heat exchanger shell; (v) attaching the secondportion of the first heat exchanger shell to a second module frame withat least two connecting members that are rigidly attached to the secondportion of the first heat exchanger shell, the first module framecomprising a plurality of columns connected by cross-members; and (w)telescoping the first coil wound mandrel into the first portion of thefirst heat exchanger shell through the first open face while the firstshell longitudinal axis is in a substantially horizontal orientation;wherein step (f) comprises, after performing steps (e) and (w), closingthe first open face of the first heat exchanger shell by joining thefirst portion of the first heat exchanger shell to the second portion ofthe first heat exchanger shell and joining the first module frame to thesecond module frame to form the first heat exchange module.
 17. A methodcomprising: (a) suspending a coil wound heat exchanger in asubstantially vertical orientation above a platform with at least onesaddle and at least one lug that are each rigidly connected to the coilwound heat exchanger and are each connected to a module frame; (b)rigidly affixing the at least one lug to the module frame; (c) enablingthe at least one saddle to move relative to the module frame in adirection parallel to a longitudinal axis of the coil wound heatexchanger when the coil wound heat exchanger transitions from ambienttemperature to an operating temperature; (d) telescoping a coil woundmandrel into a shell of the coil wound heat exchanger with the shell ofthe coil wound heat exchanger in a substantially horizontal orientation;and (e) supporting the coil wound heat exchanger during step (d) usingthe at least one saddle and at least one lug that suspend the coil woundheat exchanger in step (a).